Linseed oil sitting in a bowl, or spread on the surface of wood, is perfectly safe. But a linseed oil soaked rag provides a vastly increase surface area, so the oxidation happens faster, and the rag can provide insulation, trapping the heat. The increased temperature speeds up the oxidation even more, which raises the temperature even more, and the runaway feedback can quickly result in temperatures that will cause the rag to spontaneously burst into flame. This isn't one of those "do not drive car while sunscreen is in place" warnings. This is one of those "keep your finger off the trigger until you have the gun pointed at something you want to shoot" warnings. Rags soaked in linseed oil will catch fire, if you don't handle them properly, and they can do so far more quickly than you might think.
There is a mandatory safety class you have to take where they walk you around the shop and make sure that you know how each major machine works and general shop safety. You also have to sign a waiver saying you are participating at your own risk. You DO NOT have to take that safety class if you are signing up for one of their classes. They will cover those basics during the class.
Post Woodworking’s Hampton shed is a major standout in design. The sleek farmers porch immediately draws the eye into its pure New England charm and provides the utility of shade and a cool place to sit and enjoy a cold one. Like all of our sheds, the six-panel doors which add to the structure’s aesthetic come standard. They’re made out of fiberglass to last through many decades out in the elements.